Adapter assembly for fiber optic connectors

ABSTRACT

An adapter assembly is provided for holding two individual fiber optic connectors in generally parallel side-by-side alignment. The assembly includes a body having a pair of holding portions adapted for holding the fiber optic connectors in a substantially side-by-side relationship. A separate spring is mounted on the body and is adapted for cooperating with the body to bias the fiber optic connectors to a substantially parallel relationship.

This is a divisional of application(s) Ser. No. 08/373,175 filed on Jan.17, 1995 U.S. Pat. No. 5,554,180.

FIELD OF THE INVENTION

This invention generally relates to the art of fiber optic connectorassemblies and, particularly, to an adapter assembly for holding a pairof individual fiber optic connectors.

BACKGROUND OF THE INVENTION

Fiber optic devices use single or multiple strands of fibers each havingan inner circular glass core coated with a circumferential claddinghaving a different index of refraction. Light is transmitted along thecore and totally reflected from the interface between the core andcladding. Such devices can be used as transmission lines fortransmitting information bearing light energy. A transmission line canbe formed from a single fiber or it can include a plurality of fibersbundled together. Additionally, several transmission lines can bearranged in parallel for the simultaneous transmission of informationalong each of the separate lines.

Originally, fiber optic systems utilized simplex interconnection systemswith single connector plugs terminating single fiber optic cables. In asimplex system, either transmission or reception of information can takeplace at one time. Consequently, simplex systems are limited in theamount of information that they can transmit and receive during a givenperiod of time.

To increase the amount of information that can be communicated overfiber optic systems, multi-channel systems were developed. Suchmulti-channel systems include, for example, duplex connector plugs andcables which are capable of simultaneous transmission and reception.Thus, using a duplex system enables information to be transmitted at amuch higher rate.

Despite the advantages, multi-channel fiber optic systems are relativelynew, and many simplex systems and parts are already in use, for example,ST and SC type connectors. Consequently, simplex parts are readilyavailable and less expensive because there is an existent inventory.Moreover, it would be difficult if not cost prohibitive to retrofitexisting simplex systems with dedicated duplex or other multi-channelparts. Consequently, a need exists for an interconnection system whichis compatible with both simplex and duplex parts and which permits theinterconnection of simplex parts in a duplex configuration to provideduplex data transmission. Several designs have been proposed to addressthis problem. Typically, they involve an adapter structure which clampson two individual connector housings to hold the two connectors in aside-by-side relationship forming a duplex connector.

The present invention is directed to providing an improved, morereliable adapter structure or assembly for holding a pair of connectorsin a side-by-side relationship and ensuring that the connectors aremaintained in a generally parallel relationship and alignment.

SUMMARY OF THE INVENTION

An object, therefore, of the invention is to provide a new and improvedadapter assembly for holding two individual fiber optic connectors ingenerally parallel side-by-side alignment.

In the exemplary embodiments of the invention, the adapter assemblyincludes a body having a pair of holding portions adapted for holdingthe fiber optic connectors in a substantially side-by-side relationship.A separate spring means is mounted on the body and is adapted forcooperating with the body to bias the fiber optic connectors to asubstantially parallel relationship.

As disclosed herein, the body is generally H-shaped with two opposingpairs of leg portions defining the pair of holding portions. The pairsof leg portions are joined by a bridge portion, and the spring means ismounted on the bridge portion.

In one embodiment of the invention, the spring means comprises a coilspring mounted in a through hole in the bridge portion of the H-shapedbody. Opposite ends of the coil spring are maintained in opposingbiasing engagement with the fiber optic connectors.

In another embodiment of the invention, the spring means comprises aleaf spring mounted intermediate its ends to the body near the bridgeportion thereof. Opposite ends of the leaf spring are maintained inbiasing engagement with the fiber optic connectors.

In both embodiments of the invention, lost motion means are provided tomount the fiber optic connectors to the holding portions of the body toprovide floating motion between the connectors and the body.

Other objects, features and advantages of the invention will be apparentfrom the following detailed description taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of this invention which are believed to be novel are setforth with particularity in the appended claims. The invention, togetherwith its objects and the advantages thereof, may be best understood byreference to the following description taken in conjunction with theaccompanying drawings, in which like reference numerals identify likeelements in the figures and in which:

FIG. 1 is a perspective view of an adapter assembly according to theinvention and holding two individual fiber optic connectors, inconjunction with a duplex receptacle for the connectors;

FIG. 2 is a perspective view of the body of the adapter assembly;

FIG. 3 is a vertical section taken generally along line 3--3 of FIG. 1;

FIG. 4 is a view similar to that of FIG. 3, but showing one of the fiberoptic connectors out of alignment;

FIG. 5 is a top plan view of a second embodiment of an adapter assemblyaccording to the invention;

FIG. 6 is a vertical section taken generally along line 6--6 of FIG. 5;

FIG. 7 is a vertical section taken generally along line 7--7 of FIG. 5;and

FIG. 8 is a top plan view similar to that of FIG. 5, but showing bothfiber optic connectors out of alignment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in greater detail, FIGS. 1-4 show a firstembodiment of the invention, and FIGS. 5-8 show a second embodiment ofthe invention. Although both embodiments use a common concept ofproviding an adapter assembly with a body and a separate spring means,the embodiment of FIGS. 1-4 will be described first, followed by adescription of the embodiment of FIGS. 5-8.

Referring first to FIG. 1, the invention is incorporated in an adapterassembly, generally designated 10, designed for holding two individualfiber optic connectors, generally designated 12, in generally parallelside-by-side alignment so that the connectors can be easily insertedinto a duplex receptacle, generally designated 14, or other duplexconnecting device. Each fiber optic connector 12 includes a generallyrectangular housing 16 with a boot 18 projecting from the rear thereoffor embracing a fiber optic cable 20. The cable 20 contains an opticalfiber 22 which, as explained in the "Background" above, includes aninner circular glass core surrounded by circumferential cladding. Thefibers 22 are shown in FIG. 1 centered within ferrules 24 of the fiberoptic connectors.

As stated above, adapter assembly 10 is designed for holding connectors12 in generally parallel side-by-side alignment for easy insertion ofthe connectors into duplex receptacle 14. The receptacle has a pair ofrectangular sockets 26 on opposite sides of a flange 28. Connectors 12are inserted into the sockets on the right-hand side of flange 28 in thedirection of arrows "A". The front edges or corners of the connectorhousings 16 are chamfered, as at 30, to facilitate guiding theconnectors into the sockets of duplex receptacle 14. A second pair ofconnectors or other complementary connecting devices are inserted intothe left-hand sockets 26 of duplex receptacle 14 for mating withconnectors 12. When mated, light is transmitted along fibers 22 to andfrom the connectors and the mating connecting devices.

Referring to FIG. 2 in conjunction with FIG. 1, adapter assembly 10includes a body, generally designated 32, which has a generally H-shapeas seen best in FIG. 2. Body 32 is a unitary structure which can beintegrally molded of substantially rigid plastic material. The H-shapedconfiguration of the body defines two pairs of leg portions 34 joined bya bridge portion 36. Each pair of leg portions 34 defines a holdingportion of body 32 for receiving fiber optic connectors 12 on oppositesides of bridge portion 36 as seen in FIG. 1. The leg portions havelaterally or transversely elongated apertures 38 for receivingprojections 40 from housings 16 of connectors 12. For purposes describedhereinafter, as shown in FIGS. 2, 3 and 4, a hole 42 extends completelythrough bridge portion 36 of the H-shaped body 32. Lastly, the innerdistal edges of leg portions 34 are chamfered, as at 44, to facilitateinserting the connectors into opposite sides of the adapter assembly inthe direction of arrow "B".

Referring to FIG. 3 in conjunction with FIGS. 1 and 2, a separate springmeans in the form of a coil spring 46 is mounted on body 32 of adapterassembly 10 by locating the coil spring in through hole 42 in bridgeportion 36 of the H-shaped body. In this manner, opposite ends of thecoil spring are maintained in opposing biasing engagement with the fiberoptic connectors as seen in FIG. 3. When in this assembled condition,the coil spring biases the connectors laterally outwardly in oppositedirections and, thereby, biases projections 40 of the connector housingslaterally outwardly against the outer edges of apertures 38 in legportions 34 of the adapter body. This is effective to maintain theconnectors in generally parallel relationship. In other words, while thebody 32 of adapter assembly 10 maintains the connectors in asubstantially side-by-side relationship, the spring means cooperateswith the body to bias the connectors to a substantially parallelrelationship, all of which is effective to facilitate insertion of theconnectors into sockets 26 of duplex receptacle 14 (FIG. 1).

FIG. 4 shows a condition wherein the right-hand connector assembly 12shown therein has been cocked for some reason, such as by a userengaging the connector initially with one of the sockets of the duplexreceptacle in an out-of-alignment orientation. It can be seen thatprojections 40 and apertures 38 function as a sort of lost motion meansmounting the fiber optic connectors in the adapter assembly to providefloating motion between the connectors and the assembly. It also can beseen how coil spring 46 yields to allow for this floating motion. Therange of floating motion, of course, is limited to ensure that theconnector assemblies can be inserted into the sockets of the duplexreceptacle. Nevertheless, coil spring 46 continues to bias theconnectors toward a substantially parallel relationship while H-shapedbody 32 maintains the connectors in a substantially side-by-siderelationship.

As stated above, FIGS. 5-8 show a second embodiment of the invention.This embodiment is substantially identical to the embodiment describedabove in relation to FIGS. 1-4, except for the form of the spring meansof the adapter assembly and direction of the spring force. Therefore,like numerals have been applied in FIGS. 5-8 corresponding to likecomponents described above in relation to FIG. 1-4.

More particularly, adapter assembly 10 in FIGS. 5-8 again include agenerally H-shaped body, with the H-shaped configuration defining twoopposing pairs of leg portions 34 joined by a bridge portion 36.Projections 40 project from housings 16 of fiber optic connectors 12into apertures 38 in the leg portions of the H-shaped body. However, itshould be noted in FIG. 5 that projections 40 are biased forwardlyagainst edges 38a of apertures 38.

In the embodiment of FIGS. 5-8, the separate spring means of the adapterassembly is provided by a leaf spring 50 secured by a fastening means52, such as a bolt, to a post 54 which projects rearwardly from bridgeportion 36 of the H-shaped body. The post may be molded integrally withthe unitary body. Leaf spring 50 has bowed opposite ends 50a forapplying biasing forces against rear faces 56 of connector housings 16in the direction of arrows "C" (FIG. 5).

In operation of the embodiment in FIGS. 5-8, when the assembly is in astatic condition, opposite ends 50a of leaf spring 50 bias the fiberoptic connectors forwardly such that projections 40 abut against frontedges 38a of apertures 38. In this condition, the leaf spring iseffective for maintaining the connectors in a substantially parallelrelationship as seen in FIG. 5, while H-shaped body 32, again, maintainsthe connectors in a side-by-side relationship. FIGS. 6 and 7 show rearend and sectional views of this condition. However, it can be seen inFIG. 7 that apertures 38 are longer laterally than the width ofprojections 40 to allow for a lost motion type floating action betweenthe connectors and the adapter body as described above in relation tothe embodiment of FIGS. 1-4.

Lastly, FIG. 8 shows that fiber optic connectors 12 can becomeout-of-alignment due to the floating action allowed by the lost motionmeans of enlarging apertures 38 relative to projections 40. However, thedistal ends 50a of leaf spring 50 provide a biasing action in thedirection of arrows "C" which tend to force the connectors forwardly andforce the projections against the forward edges 38a of projections 30 inan attempt to maintain the connectors in a substantially parallelrelationship.

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or centralcharacteristics thereof. The present examples and embodiments,therefore, are to be considered in all respects as illustrative and notrestrictive, and the invention is not to be limited to the details givenherein.

We claim:
 1. An adapter assembly for holding two individual fiber opticconnectors in generally parallel side-by-side alignment, comprising:abody having a pair of holding portions adapted for holding said fiberoptic connectors in a substantially side-by-side relationship; lostmotion means mounting the fiber optic connectors to said holdingportions to provide floating motion between the connectors and the body,said lost motion means including complementary interengaging abutmentsurfaces between the connectors and the body generally parallel to saidparallel alignment direction; and a leaf spring mounted intermediate itsends to the body, with opposite ends of the leaf spring in biasingengagement with the fiber optic connectors to bias the fiber opticconnectors to a substantially parallel relationship.
 2. The adapterassembly of claim 1 wherein said lost motion means comprises enlargedapertures in the body receiving projections from the connectors, theapertures and projections defining said abutment surfaces.
 3. Theadapter assembly of claim 1 wherein said body is generally H-shaped withtwo opposing pairs of leg portions defining said pair of holdingportions.
 4. The adapter assembly of claim 3 wherein said pairs of legportions are joined by a bridgeportion and said leaf spring is mountedintermediate its ends to the body near the bridge portion.